The lock which provides access in and out of Waalwijk harbour is nine metres wide. ONE has a moulded beam of 7.8 metres and we also had to take into account the rubbing strakes, which added another 40 centimetres to the total width. That may sound like a simple calculation, then, but a further complicating factor was the lock bridge, which does not open up fully vertically. This slight incline required further planning to ensure the superstructure could also pass through the raised bridge unscathed.

Smooth operators
One of the crucial aspects of an operation like this is to ensure a smooth passage. We therefore teamed up with an expert tug boat company to push-pull ONE through the lock rather than having the yacht jolt into first gear at the slow speed required to move forward. One tug was fixed to the transom, the other to the bow using a temporary X-shaped frame attachment to ensure a fixed connection.

For the bow-end tug we also floated a small pontoon on the port side to serve as a guide. This was precisely aligned to leave a 20-centimetre gap between the yacht’s top coat and the concrete of the lock so that only the pontoon could potentially be scratched. Everything went perfectly and ONE was duly able to continue on her four-hour cruise to the Hellevoetsluis gateway to the North Sea for over a week of stringent sea trials.

In the flow
Another complex parameter to take into account with the journey from the Van der Valk yard is the time of year. The water was relatively low on the June day that ONE was on the move but in earlier months we have to consider the potential for higher water levels due to rain and snow melting in Switzerland. The latter swells the river Rhine and, ultimately, one of that mighty waterway’s tributaries, the river Maas. This water then flows into the canal, raising water levels and making the distance between superstructure and bridge even tighter.

This whole operation with ONE therefore served as a test run for even larger projects currently in build at Van der Valk. Jangada, for instance has an overall beam of 8.5 metres and is slightly higher, leaving a margin of just 15 centimetres with the bridge and 18 on the waterline. Samba is the same measurement at her widest point and we’ll also have to be very careful with her wing stations. Then there is the fact that EVO is likely to be going through the lock in January 2026 when the waters might be especially high. We look forward to getting the calculators and tape measures out again then!